The year is 50BC and Gaul is entirely occupied by the Romans. Well, not entirely. One small village of indomitable Gauls still holds out against the invaders. The year is 2009AD. France has been entirely conquered by baseball hats, Big Macs and Hollywood films. Well, not entirely. One indomitable enclave of French culture still holds out, and even thrives.

The Asterix series of cartoon books, France's most lucrative literary export by far, will celebrate its 50th anniversary from next week with a series of exhibitions and special events and a new album of stories.

Asterix recounts the unlikely adventures of a village of ancient Gauls who refuse to bow to the power of Rome. The hero is a short, cocky, clever, hyper-energetic leader, who claims to have a magic potion to defend the Gaulish way of life. Any accidental parallel with contemporary French politics ends there. Asterix the Gaul has no tall, glamorous wife of Roman origin; he has no wife at all. Instead, he has a platonic friendship with a man-mountain called Obelix and a dog called Idéfix (or in the English language version, Dogmatix).

Their comic adventures have been translated into 107 languages and have sold 325 million copies worldwide. The three, non-cartoon Asterix films made in the past 10 years, with a heavily padded Gérard Depardieu playing Obelix, have become the most successful series of French films in history.

In a reversal of the plot since 50BC, the world therefore has been entirely conquered by the Gauls. Well, not entirely. Some indomitable enclaves continue to hold out. Despite excellent English translations, Asterix has never really caught on in the US and is only a limited success in Britain. (In Italy, although the series presents the Romans as a bunch of arrogant, cowardly, quarrelsome nincompoops, it has been surprisingly popular.)

Asterix is, above all, a story of two beautiful friendships, first between Asterix and Obelix and second between their creators, Albert Uderzo, who drew the cartoons, and René Goscinny, who wrote the original stories. Although the saga is a wry tribute to Gallic pride and cussedness, neither man was of French origin. Uderzo's parents were Italian. Goscinny, who died in 1977, came from a Polish-Jewish family.

The good-natured façade of the Asterix saga has been shattered recently by a public row between Uderzo (82) who is still drawing and writing, and his only daughter, Sylvie. In 2007, Uderzo fired Sylvie from his publishing firm. In 2008, he sold the company and the rights to France's biggest publisher, Hachette. He also agreed – reversing a previous deal – that others could extend the series after his death.

Sylvie accused her father, in an open letter to Le Monde, of "betraying" the spirit of Asterix by selling off a "symbol of France's cultural heritage" to a company "driven mostly by profit". Uderzo responded that he had fired his daughter, and her husband, because of their "filial ingratitude and obsession with money". The episode, only partly settled by a court judgment in Sylvie's favour this year, is reminiscent of the 15th Asterix album, Asterix et la Zizanie (literally, Asterix and the huge bust-up).

This book (called Asterix and the Roman Agent in English) tells of a poisonous Roman, Tullius Detritus, who can divide the best of friends and families with a couple of ill-chosen words. Like many other Asterix characters and sayings, Tullius has become part of the French language. The French prime minister, François Fillon, is a great Asterix fan and a sworn enemy of the labour minister Xavier Bertrand, whom he accuses of bearing malicious tales to President Nicolas Sarkozy. The satirical newspaper Le Canard Enchainé reported recently that Fillon always refers to Bertrand in private as "Tullius Detritus".

Much of the fun of the Asterix books comes from the punning names of the Gaulish or Roman characters. Replacing the jokes in the French names has been a test of the ingenuity of translators worldwide. Speak it not in Gaul, but the English language versions are sometimes cleverer and funnier than the originals. The chief Druid, who mixes the magic potion, is "Panoramix" in French, which is rather dull. In Britain, he is "Getafix". In America, he is "Readymix" or "Magicmix".

The village chief is "Abraracoucix" in the original. In English, he becomes, "Vitalstastix" (UK) and "Macroeconomix" (US). His wife is "Bonemine" in French, "Impedimenta" in Britain and "Belladonna" in the US. The tuneless village bard, who is never allowed to sing and looks rather like the former French prime minister, Dominique de Villepin, is "Assurancetourix" in French. In Britain, he is "Cacofonix" and in the US "Malacoustix". The fishmonger's wife is "Ielosubmarine" (Yellow Submarine) in French and "Bacteria" in English.

Asterix appeared for the first time in a cartoon magazine called Pilote on 29 October 1959. Goscinny and Uderzo thought up most of the main characters in a 30-minute brain-storming session in a council flat in Paris. Goscinny set out originally to mock, rather than to glorify, French insularity. Charles de Gaulle had just become president of the republic. France versus the Rest of the World rapidly became a theme of the 1960s. Asterix took off.

To commemorate the half-centenary, Uderzo – who now writes the stories and still does the preliminary drawings – will publish next week an album of short stories, Asterix et Le Livre d'Or (Asterix and the Golden Book), in which many characters from the past 50 years reappear, and there will be a series of celebrations in Paris.

In interviews to mark the half-centenary, Uderzo again defended his decision to allow new Asterix albums to be written and drawn after his death. He said he had decided to abandon the example set by Hergé, the creator of Tintin, who banned posthumous sequels. "When no more adventures are added to a series, little by little it dies," he said. "We know that because each time we publish a new book it boosts the sales of all the others."